In the same way that Candy Crush Saga is King's take on Bejeweled, and Papa Pear Saga is its Peggle, Bubble Witch Saga 2 has clearly been 'influenced' by Puzzle Bobble / Bust-a-Move.

It sports the same core mechanic of shooting coloured bubbles up towards a hanging stack. The aim being to free up large clusters by strategically targeting the supporting structure.

Taito package

Like Taito's classic puzzler, the art to this lies in bouncing your bubbles off the side of the playing field. You get an aim guide, but it's only good for gauging the initial direction of your shot and a little of the rebound angle.

This well worn system is applied to three level types. The most basic is Clear the Top, which sees you trying to get to the top of the bubble stack. Victory comes when you pop six bubbles in the top row.

Then there's Save the Animals, which sees you freeing trapped animals by popping the surrounding bubbles.

Finally, there's Free the Ghost, which features a whirl of bubbles surrounding a central apparition.

You need to pop the bubbles, but each one that bursts nudges the rest, making your next shot a little tougher.

Level Peggling

While the core gameplay is pure Puzzle Bobble, there are a couple of notable variations here. First is the scoring system.

Once you've freed up the bubbles, they fall into a Peggle-like arrangement of baskets at the bottom of the screen, each one representing a certain score. There are also spider-shaped bumpers that float just above these baskets, granting additional points.

There's a certain degree of excitement here, but it can be really frustrating to be robbed of a three star score simply because your bubbles didn't quite bounce right.

Another difference is that the number of shots you have is strictly limited. This leads to some truly annoying moments tied into the game's freemium structure.

IAPs explained

You need to pay for everything, including lives, extra bubbles, and power-up bubbles, with gold.

Gold costs 69p for 10, £1.99 for 32, stretching right up to £34.99 for 650.

Five lives or five extra bubbles at the end of a failed level will cost you 12 gold bars.

Level 19 is a Free the Ghost level and I kept finding myself coming up half a dozen bubbles or so short of completion.

After making serene progress up to that point, I suddenly bumped into the game's lives system, which requires you to wait 30 minutes to recharge each one.

So I did that on a couple of occasions. Sure enough, I came up short again and again.

The bubbles the game gave me weren't quite what I needed to close the level out. I paid for five extra bubbles on a few occasions, but it didn't quite push me over the line.

Eventually I purchased some more lives using the game's gold currency, which can be bought with IAPs. You can also ask your friends to gift you some lives, but as I'm not on Facebook, that wasn't much use.

Level 20 was even worse. Here was a sprawling Clear the Top level that offered a number of snaking bubble paths just ripe for exploitation.

The thing is, this required the precise colour to be given to me, and I consistently found that the game didn't give me quite what I needed.

It's almost like I was being prompted to spend on the game's special bubbles (the rainbow acts as any colour, the fireball eats a path through anything), or more bubbles, or a bunch of extra lives. Hmmm.

Any witch way but loose

Bubble Witch Saga 2 is undoubtedly good fun. How could it not be? It's an accomplished take-off of a classic casual puzzler, executed with a clean style and lots of whizzy-bangy visual rewards. That's what King does so well, after all.

But I was surprised to see the game's payment-prompting freemium underpinnings showing through so blatantly.

Millions of casual gamers will doubtless fall under Bubble Witch Saga 2's spell, and the skill King has exhibited in getting to this enviable position shouldn't be underestimated.

More seasoned gamers, however, will find the freemium execution too crude, the skill-to-luck ratio too unbalanced, and the bar for success a little too stage-managed to easily swallow this particular concoction.